Green River

The Green River is the 730-mile chief tributary of the Colorado River, located in Wyoming, Utah, and Colorado. In 1776, the river was discovered by two Spanish friars who named it "Rio de San Buenaventura", and later Spanish and Mexican explorers called it the "Rio Verde" ("green river"). From the 1840s to 1860s, hundreds of thousands of emigrants crossed the trail as part of the Oregon Trail, California Trail, and Mormon Trail.